Cantoris, isn't that what perhaps far more of gambling is about than perhaps even gamblers know? Yourself versus X - name the enemy? Seeing if your strategies, wiles, knowledge, intuition and bravado overcome the opposition - in Mr McManus's case, the bookies and now exchanges (I assume he uses those, too). Outwitting and outflanking in the way military campaigns are led. You're your own general, your money is your troops - into battle you go against a worthy foe! Yes, there's got to be a drive to overpower the other one, whether it's Blue Square or Betdaq, and the win is not so much about adding large lumps to one's bank balance as about validating one's own judgment.
I think for many gamblers, in particular high-stakes rollers, this is the kick. Of course they may lose sometimes, but to them that's just a bit of expected collateral damage on the way to sending in their troops again, this time to overwhelm and take away the latest trophy.
I imagine it's fascinating to study the psyches of the world's top gamblers - which must include those "gambling" on launching new businesses or pushing new inventions as much as roulette players and spread bettors - I'm sure there are common factors, with the will to win being a manifestation of aggression, but not one that takes too many real lives.